OGS ONE Gas Inc

Exhibit 1.1

ONE GAS, INC.

$300,000,000 5.10% Senior Notes due 2029

Underwriting Agreement

December 11, 2023

J.P. Morgan Securities LLC

383 Madison Avenue

New York, New York 10179

Mizuho Securities USA LLC

1271 Avenue of the Americas

New York, New York 10020

U.S. Bancorp Investments, Inc.

214 North Tryon Street, 26th Floor

Charlotte, North Carolina 28202

As Representatives of the

several Underwriters listed

in Schedule 1 hereto

Ladies and Gentlemen:

ONE Gas, Inc., an Oklahoma corporation (the “Company”), proposes to issue and sell to the several Underwriters listed in Schedule 1 hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), $300,000,000 aggregate principal amount of its 5.10% Senior Notes due 2029 (the “Securities”). The Securities will be issued pursuant to an Indenture dated as of January 27, 2014 (the “Base Indenture”) between the Company, and U.S. Bank Trust Company, National Association (successor in interest to U.S. Bank National Association), as trustee (the “Trustee”), as amended and supplemented and as further supplemented by Supplemental Indenture No. 7 to be dated as of December 13, 2023 (the “Supplemental Indenture” and together with the Base Indenture, the “Indenture”).

The Company hereby confirms its agreement with the several Underwriters concerning the purchase and sale of the Securities, as follows:

1. Registration Statement. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 (File No. 333-269966), including a prospectus, relating to certain securities (the “Shelf Securities”), including the Securities, to be issued from time to time by the Company. The registration statement as amended to the date of this Underwriting Agreement (the “Agreement”), including the information (if any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430A or Rule 430B under the Securities Act of 1933, as amended (the “Securities Act”), is hereinafter referred to as the “Registration

Statement,” and the related prospectus covering the Shelf Securities dated February 23, 2023, is hereinafter referred to as the “Basic Prospectus.” The Basic Prospectus, as supplemented by the prospectus supplement specifically relating to the Securities in the form first used to confirm sales of the Securities (or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Prospectus,” and the term “preliminary prospectus” means any preliminary form of the Prospectus including the preliminary prospectus supplement relating to the Securities dated December 11, 2023 (the “Preliminary Prospectus”). For purposes of this Agreement, “free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act. As used herein, the terms “Registration Statement,” “Basic Prospectus,” “preliminary prospectus,” “Pricing Disclosure Package” (as defined below) and “Prospectus” shall include the documents, if any, incorporated by reference therein as of the Applicable Time (as defined below). The terms “supplement,” “amendment,” and “amend” as used herein with respect to the Registration Statement, the Basic Prospectus, the Pricing Disclosure Package, any preliminary prospectus or the Prospectus shall include all documents filed by the Company with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that are deemed to be incorporated by reference therein after the Applicable Time.

At or prior to 3:00 p.m., New York City time, on December 11, 2023, the time when sales of the Securities were first made (the “Applicable Time”), the Company had prepared the following information (collectively, the “Pricing Disclosure Package”): the Preliminary Prospectus dated December 11, 2023, and each free-writing prospectus listed on Annex A hereto.

2. Purchase and Sale of the Securities.

(a) The Company agrees to issue and sell the Securities to the several Underwriters as provided in this Agreement, and each Underwriter, on the basis of the representations, warranties and agreements set forth herein and subject to the conditions set forth herein, agrees, severally and not jointly, to purchase from the Company the respective principal amount of Securities set forth opposite such Underwriter’s name in Schedule 1 hereto at a price equal to 99.261% of the principal amount thereof plus accrued interest, if any, from December 13, 2023 to the Closing Date (as defined below). The Company will not be obligated to deliver any of the Securities except upon payment for all the Securities to be purchased as provided herein.

(b) The Company understands that the Underwriters intend to make a public offering of the Securities as soon after the effectiveness of this Agreement as in the judgment of the Representatives is advisable, and initially to offer the Securities on the terms set forth in the Pricing Disclosure Package. The Company acknowledges and agrees that the Underwriters may offer and sell Securities to or through any affiliate of an Underwriter and that any such affiliate may offer and sell Securities purchased by it to or through any Underwriter.

(c) Payment for and delivery of the Securities will be made at the offices of Hunton Andrews Kurth LLP at 10:00 A.M., New York City time, on December 13, 2023, or at such other time or place on the same or such other date, not later than the fifth business day thereafter, as the Representatives and the Company may agree upon in writing. The time and date of such payment and delivery is referred to herein as the “Closing Date.”

(d) Payment for the Securities shall be made by wire transfer in immediately available funds to the account(s) specified by the Company to the Representatives against delivery to the nominee of The Depository Trust Company (“DTC”), for the account of the Underwriters, of one or more global notes representing the Securities (collectively, the “Global Note”), with any transfer taxes payable in connection with the sale of the Securities duly paid by the Company. The Global Note will be made available for inspection by the Representatives not later than 1:00 P.M., New York City time, on the business day prior to the Closing Date.

2

(e) The Company acknowledges and agrees that each Underwriter is acting solely in the capacity of an arm’s length contractual counterparty to the Company with respect to the offering of Securities contemplated hereby (including in connection with determining the terms of the offering) and not as a financial advisor or a fiduciary to, or an agent of, the Company or any other person. Additionally, neither the Representatives nor any other Underwriter is advising the Company or any other person as to any legal, tax, investment, accounting or regulatory matters in any jurisdiction. The Company shall consult with its own advisors concerning such matters and shall be responsible for making its own independent investigation and appraisal of the transactions contemplated hereby, and the Underwriters shall have no responsibility or liability to the Company with respect thereto. Any review by the Representatives or any Underwriter of the Company, the transactions contemplated hereby or other matters relating to such transactions will be performed solely for the benefit of the Representatives or such Underwriter, as the case may be, and shall not be on behalf of the Company, as the case may be, or any other person.

3. Representations and Warranties of the Company. The Company represents and warrants to each Underwriter that:

(a) Preliminary Prospectus. No order preventing or suspending the use of any Preliminary Prospectus has been issued by the Commission, and the Preliminary Prospectus, at the time of filing thereof, complied in all material respects with the Securities Act and did not contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation or warranty with respect to any statements or omissions made in reliance upon and in conformity with any Underwriter Information (as defined in Section 7(b)).

(b) Pricing Disclosure Package. The Pricing Disclosure Package, at the Applicable Time did not, and at the Closing Date will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation or warranty with respect to any statements or omissions made in reliance upon and in conformity with information relating to any Underwriter Information. No statement of material fact included in the Prospectus has been omitted from the Pricing Disclosure Package and no statement of material fact in the Pricing Disclosure Package that is required to be included in the Prospectus has been omitted therefrom.

(c) Issuer Free Writing Prospectus. The Company (including its agents and representatives, other than the Underwriters in their capacity as such) has not prepared, made, used, authorized, approved or referred to and will not prepare, make, use, authorize, approve or refer to any “written communication” (as defined in Rule 405 under the Securities Act) that constitutes an offer to sell or solicitation of an offer to buy the Securities (each such communication by the Company or its agents and representatives (other than a communication referred to in clauses (i) (ii) and (iii) below) an “Issuer Free Writing Prospectus”) other than (i) any document not constituting a prospectus pursuant to Section 2(a)(10)(a) of the Securities Act or Rule 134 under the Securities Act, (ii) the Preliminary Prospectus, (iii) the Prospectus, (iv) the documents listed on Annex A hereto, including a Pricing Term Sheet substantially in the form of Annex B hereto, which constitute part of the Pricing Disclosure Package and (v) any electronic road show or other written communications, in each case approved in writing in advance by the Representatives. Each such Issuer Free Writing Prospectus complies in all material respects with the Securities Act, has been or will be (within the time period specified in Rule 433) filed in accordance with the Securities Act (to the extent required thereby) and, when taken together with the Preliminary Prospectus, such Issuer

3

Free Writing Prospectus, at the Applicable Time, did not, and at the Closing Date will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation or warranty with respect to any statements or omissions made in each such Issuer Free Writing Prospectus in reliance upon and in conformity with any Underwriter Information.

(d) Registration Statement and Prospectus. The Registration Statement is an “automatic shelf registration statement” as defined under Rule 405 of the Securities Act that has been filed with the Commission not earlier than three years prior to the date hereof; and no notice of objection of the Commission to the use of such registration statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act has been received by the Company. No order suspending the effectiveness of the Registration Statement has been issued by the Commission and no proceeding for that purpose or pursuant to Section 8A of the Securities Act against the Company or related to the offering has been initiated or threatened by the Commission; as of the applicable effective date of the Registration Statement and any amendment thereto, the Registration Statement complied and will comply in all material respects with the Securities Act and the Trust Indenture Act of 1939, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Trust Indenture Act”), and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading; and as of the date of the Prospectus and any amendment or supplement thereto and as of the Closing Date, the Prospectus does not and will not contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that the Company makes no representation or warranty with respect to (i) that part of the Registration Statement that constitutes the Statement of Eligibility and Qualification (Form T-1) of the Trustee under the Trust Indenture Act or (ii) any statements or omissions made in reliance upon and in conformity with Underwriter Information.

(e) Incorporated Documents. The documents incorporated by reference in each of the Registration Statement, the Prospectus and the Pricing Disclosure Package, when they were filed with the Commission conformed in all material respects to the requirements of the Exchange Act, and none of such documents contained any untrue statement of a material fact or omitted to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and any further documents so filed and incorporated by reference in the Registration Statement, the Prospectus or the Pricing Disclosure Package, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable, and will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(f) Financial Statements. The financial statements and the related notes thereto included or incorporated by reference in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus comply in all material respects with the applicable requirements of the Securities Act and the Exchange Act, as applicable, and present fairly in all material respects the financial position of the Company and its subsidiaries as of the dates indicated and the results of their operations and the changes in their cash flows for the periods specified; such financial statements have been prepared in conformity with generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods covered thereby, and the supporting schedules included or incorporated by reference in each of the Registration Statement, the Prospectus and the Pricing Disclosure Package present fairly in all material respects the information required to be stated therein; and the other financial information included or incorporated by reference in each of the Registration Statement, the Pricing Disclosure

4

Package and the Prospectus has been derived from the accounting records of the Company and its subsidiaries and presents fairly in all material respects the information shown thereby. The interactive data in eXtensible Business Reporting Language (“XBRL Data”) included or incorporated by reference in the Registration Statement, the Prospectus and the Pricing Disclosure Package fairly presents the information called for in all material respects and is prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(g) No Material Adverse Change. Since the date of the most recent financial statements of the Company included or incorporated by reference in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus, there has not been any material adverse change in the business, properties, financial position, results of operations, business affairs or business prospects of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”).

(h) Organization and Good Standing. The Company and each of its subsidiaries have been duly organized and are validly existing and in good standing under the laws of their respective jurisdictions of organization, are duly qualified to do business and are in good standing in each jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such qualification, and have all power and authority necessary to own or hold their respective properties and to conduct the businesses in which they are engaged, except where the failure to be so qualified, in good standing or have such power or authority would not, individually or in the aggregate, result in a Material Adverse Effect. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the subsidiaries listed in Exhibit 21.1 to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022, except for entities that have been omitted pursuant to Item 601(b)(21) of Regulation S-K.

(i) Capitalization. The Company has the capitalization as set for in the Pricing Disclosure Package and the Prospectus under the heading “Capitalization”; and all the outstanding shares of capital stock or other equity interests of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and are owned directly or indirectly by the Company, free and clear of any lien, charge, encumbrance, security interest, restriction on voting or transfer or any other claim of any third party, other than transfer restrictions under applicable securities laws or organizational documents, claims for taxes not yet due and payable or that are being contested in good faith by appropriate proceedings or other claims arising by operation of law.

(j) Due Authorization. The Company has full right, power and authority to execute and deliver this Agreement, the Securities and the Indenture (collectively, the “Transaction Documents”) and to perform its obligations hereunder and thereunder.

(k) The Indenture. The Indenture has been duly authorized by the Company, the Base Indenture has been duly executed and delivered by the Company and, when the Supplemental Indenture has been duly executed and delivered in accordance with its terms by each of the parties thereto, the Indenture will constitute a valid and legally binding agreement of the Company enforceable against the Company in accordance with its terms, except as enforceability may be limited by (A) applicable bankruptcy, insolvency, moratorium, reorganization, fraudulent conveyance or similar laws affecting the enforcement of creditors’ rights generally, (B) public policy limitations, or (C) equitable principles relating to enforceability (regardless of whether enforcement is considered in a proceeding in equity or at law) ((A), (B), and (C) collectively, the “Enforceability Exceptions”); and the Indenture will conform in all material respects to the requirements of the Trust Indenture Act.

5

(l) The Securities. The Securities have been duly authorized by the Company and, when duly executed, authenticated, issued and delivered as provided in the Indenture and paid for as provided herein, will be duly and validly issued and outstanding and will constitute valid and legally binding obligations of the Company, entitled to the benefits of the Indenture and enforceable against the Company in accordance with their terms, subject to the Enforceability Exceptions.

(m) Underwriting Agreement. This Agreement has been duly authorized, executed and delivered by the Company.

(n) Descriptions of the Transaction Documents. The Securities and the Indenture conform in all material respects to the descriptions thereof contained under the headings “Description of Debt Securities” and “Description of Notes” in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus.

(o) No Violation or Default. Neither the Company nor any of its subsidiaries is (i) in violation of its charter or by-laws or similar organizational documents; (ii) in default, and no event has occurred that, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any property or asset of the Company or any of its subsidiaries is subject; or (iii) in violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority, except, in the case of clauses (ii) and (iii) above, for any such default or violation that would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect.

(p) No Conflicts. The execution, delivery and performance by the Company of each of the Transaction Documents to which each is a party, the issuance and sale of the Securities and compliance by the Company with the terms of the Transaction Documents and the consummation of the transactions contemplated by the Transaction Documents will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, result in the termination, modification or acceleration of, or result in the creation or imposition of any lien, charge or encumbrance upon any property, right or asset of the Company or any of its subsidiaries pursuant to, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any property, right or asset of the Company or any of its subsidiaries is subject, (ii) result in any violation of the provisions of the charter or by-laws or similar organizational documents of the Company or any of its subsidiaries or (iii) result in the violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority, except, in the case of clauses (i) and (iii) above, for any such conflict, breach, violation, default, lien, charge or encumbrance that would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Effect.

(q) No Consents Required. No consent, approval, authorization, order, registration or qualification of or with any court or arbitrator or governmental or regulatory authority having jurisdiction over the Company is required for the execution, delivery and performance by the Company of each of the Transaction Documents, the issuance and sale of the Securities and compliance by the Company with the terms thereof and the consummation of the transactions contemplated by the Transaction Documents, except for (i) the registration of the Securities under the Securities Act, (ii) the qualification of the Indenture under the Trust Indenture Act and (iii) such consents, approvals, authorizations, orders and registrations or qualifications as have already been obtained or may be required under applicable securities laws of any state or foreign jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters.

6

(r) Legal Proceedings. Except as described in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus, there are no legal, governmental or regulatory actions, demands, claims, suits, arbitrations, inquiries or proceedings (“Actions”) or, to the knowledge of Company, investigations, pending to which the Company or any of its subsidiaries is or is reasonably likely to be a party or to which any property of the Company or any of its subsidiaries is or is reasonably likely to be the subject that, individually or in the aggregate, if determined adversely to the Company or any of its subsidiaries, could reasonably be expected to have a Material Adverse Effect; no such Actions or investigations which could reasonably be expected to have a Material Adverse Effect have been threatened or, to the knowledge of the Company, contemplated by any governmental or regulatory authority; and (i) there are no current or pending Actions that are required under the Securities Act to be described in the Registration Statement, the Pricing Disclosure Package or the Prospectus that are not so described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and (ii) there are no statutes, regulations or contracts or other documents that are required under the Securities Act to be filed as exhibits to the Registration Statement or described in the Registration Statement and the Prospectus that are not so filed as exhibits to the Registration Statement or described in the Registration Statement, the Pricing Disclosure Package and the Prospectus.

(s) Independent Accountants. PricewaterhouseCoopers LLP, who has certified certain financial statements of the Company and its subsidiaries is an independent registered public accounting firm with respect to the Company and its subsidiaries within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Securities Act.

(t) Title to Real and Personal Property. The Company and its subsidiaries have good title to, or have valid rights to lease or otherwise use, all items of real and personal property that are material to the respective businesses of the Company and its subsidiaries, in each case free and clear of all liens, encumbrances, claims and defects and imperfections of title except those that could not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect.

(u) Intellectual Property. (i) The Company and its subsidiaries own, possess, license or have the right to use all material patents, patent applications, trademarks, service marks, trade names, trademark registrations, service mark registrations, domain names and other source indicators, copyrights and copyrightable works, know-how, trade secrets, systems, procedures, proprietary or confidential information and all other worldwide intellectual property, industrial property and proprietary rights (collectively, “Intellectual Property”) used in the conduct of their respective businesses, except where the failure to own, possess, license or have the right to use any Intellectual Property could not reasonably be expected to result in a Material Adverse Effect; (ii) the Company and its subsidiaries have not received any written notice of any claim relating to Intellectual Property; and (iii) to the knowledge of the Company, the Intellectual Property of the Company and their subsidiaries is not being infringed, misappropriated or otherwise violated by any person.

(v) Investment Company Act. The Company is not, and after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus, will not be an “investment company” or an entity “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission thereunder (collectively, the “Investment Company Act”).

7

(w) Taxes. The Company and its subsidiaries have (i) paid all U.S. federal, state, local and foreign taxes due and payable, other than those being contested in good faith and for which reserves considered adequate by Company management have been provided and (ii) timely filed all tax returns required to be filed through the date hereof (taking into account permitted extensions thereof); except in each case as otherwise disclosed in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus or where the failure to pay or file (as applicable) could not reasonably be expect to result in a Material Adverse Effect, and there is no tax deficiency that has resulted in, or could reasonably be expected to result in, a Material Adverse Effect.

(x) Licenses and Permits. The Company and its subsidiaries possess all licenses, sub-licenses, certificates, permits and other authorizations issued by, and have made all declarations and filings with, the appropriate federal, state, local or foreign governmental or regulatory authorities that are necessary for the ownership or lease of their respective properties or the conduct of their respective businesses as described in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus, except where the failure to possess or make the same would not, individually or in the aggregate, have a Material Adverse Effect.

(y) No Labor Disputes. No labor disturbance by or dispute with employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is contemplated or threatened, and the Company is not aware of any existing or imminent labor disturbance by, or dispute with, the employees of any of the Company’s or any of the Company’s subsidiaries’ principal suppliers, contractors or customers, except as would not have a Material Adverse Effect. Neither the Company nor any of its subsidiaries has received any notice of cancellation or termination with respect to any collective bargaining agreement to which it is a party.

(z) Certain Environmental Matters. Except as otherwise disclosed in each of the Registration Statement, the Pricing Disclosure Package or the Prospectus, to the knowledge of the Company: (i) the Company and its subsidiaries (x) are in compliance with all, and have not violated any, applicable federal, state and local laws (including common law), rules, regulations, requirements, decisions, judgments, decrees, orders and other legally enforceable requirements relating to pollution or the protection of human health or safety, the environment, natural resources, hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (y) have received and are in compliance with all, and have not violated any, permits, licenses, certificates or other authorizations or approvals required of them under any Environmental Laws to conduct their respective businesses; and (z) have not received notice of any actual or potential liability or obligation under or relating to, or any actual or potential violation of, any Environmental Laws, including for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, and have no knowledge of any event or condition that would reasonably be expected to result in any such notice, and (ii) there are no costs or liabilities associated with Environmental Laws of or relating to the Company or its subsidiaries, except in the case of each of (i) and (ii) above, for any such matter as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect; and (iii) except as described in each of the Pricing Disclosure Package and the Prospectus, (x) there is no proceeding that is pending, or that is known to be contemplated, against the Company or any of its subsidiaries under any Environmental Laws in which a governmental entity is also a party, other than such proceeding regarding which it is reasonably believed no monetary sanctions of $100,000 or more will be imposed, (y) the Company and its subsidiaries are not aware of any facts or issues regarding compliance with Environmental Laws, or liabilities or other obligations under Environmental Laws or concerning hazardous or toxic substances or wastes, pollutants or contaminants, that could reasonably be expected to have a material effect on the capital expenditures, earnings or competitive position of the Company and its subsidiaries, and (z) none of the Company or its subsidiaries anticipates material capital expenditures relating to any Environmental Laws.

8

(aa) Compliance with ERISA. (i) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), for which the Company or any member of its “Controlled Group” (defined as any entity, whether or not incorporated, that is under common control with the Company within the meaning of Section 4001(a)(14) of ERISA or any entity that would be regarded as a single employer with the Company under Section 414(b),(c),(m) or (o) of the Internal Revenue Code of 1986, as amended (the “Code”)) would have any liability (each, a “Plan”) has been maintained in compliance in all material respects with any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Code; (ii) for each Plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no Plan has failed (whether or not waived), or is reasonably expected to fail, to satisfy the minimum funding standards (within the meaning of Section 302 of ERISA or Section 412 of the Code) applicable to such Plan; (iii) no “reportable event” (within the meaning of Section 4043(c) of ERISA and the regulations promulgated thereunder) has occurred for which the Company or any member of its Controlled Group would have any material liability; (iv) each Plan that is intended to be qualified under Section 401(a) of the Code is so qualified, and nothing has occurred, whether by action or by failure to act, which would reasonably be expected to cause the loss of such qualification; and (v) neither the Company nor any member of the Controlled Group has incurred, nor reasonably expects to incur, any liability under Title IV of ERISA (other than contributions to the Plan or premiums to the Pension Benefit Guarantee Corporation, in the ordinary course and without default) in respect of a Plan (including a “multiemployer plan” within the meaning of Section 4001(a)(3) of ERISA).

(bb) Disclosure Controls. The Company and its subsidiaries maintain an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that complies with the requirements of the Exchange Act and that has been designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure. The Company and its subsidiaries have carried out evaluations of the effectiveness of their disclosure controls and procedures as required by Rule 13a-15 of the Exchange Act.

(cc) Accounting Controls. The Company and its subsidiaries maintain systems of “internal control over financial reporting” (as defined in Rule 13a-15(f) of the Exchange Act) that comply with the requirements of the Exchange Act and have been designed by, or under the supervision of, their respective principal executive and principal financial officers, or persons performing similar functions, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP. The Company and its subsidiaries maintain internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences; and (v) XBRL Data included or incorporated by reference in the Registration Statement, the Prospectus and the Pricing Disclosure Package is prepared in accordance with the Commission’s rules and guidelines applicable thereto. Except as disclosed in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus, there are no material weaknesses or significant deficiencies in the Company’s internal controls.

(dd) Insurance. The Company and its subsidiaries have insurance covering their respective properties, operations, personnel and businesses, which insurance is in amounts and insures against such losses and risks as are adequate to protect the Company and its subsidiaries and their respective businesses, except where the failure to do so would not reasonably be expected to have a Material Adverse Effect.

9

(ee) No Unlawful Payments. Neither the Company nor any of its subsidiaries, nor, to the knowledge of the Company, (i) any director, officer or employee of the Company or any of its subsidiaries or (ii) any agent, affiliate or other person associated with or acting on behalf of the Company or any of its subsidiaries has (A) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (B) made or taken an act in furtherance of an offer, promise or authorization of any direct or indirect unlawful payment or benefit to any foreign or domestic government official or employee, including of any government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office; (C) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977, as amended, or any applicable law or regulation implementing the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions, or committed an offence under the Bribery Act 2010 of the United Kingdom, or any other applicable anti-bribery or anti-corruption law; or (D) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including, without limitation, any rebate, payoff, influence payment, kickback or other unlawful or improper payment or benefit. The Company and its subsidiaries have instituted, maintain and enforce policies and procedures designed to promote and ensure compliance in all material respects with all applicable anti-bribery and anti-corruption laws.

(ff) Compliance with Anti-Money Laundering Laws. The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the applicable money laundering statutes of all jurisdictions where the Company or any of its subsidiaries conducts business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Anti-Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(gg) No Conflicts with Sanctions Laws. Neither the Company nor any of its subsidiaries, nor, to the knowledge of the Company, any director, officer, employee agent, affiliate or other person associated with or acting on behalf of the Company or any of its subsidiaries is currently the subject or the target of any sanctions administered or enforced by the U.S. government, (including, without limitation, the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”) or the U.S. Department of State and including, without limitation, the designation as a “specially designated national” or “blocked person”), the United Nations Security Council (“UNSC”), the European Union, His Majesty’s Treasury (“HMT”), or other relevant sanctions authority (collectively, “Sanctions”), nor is the Company, any of its subsidiaries located, organized or resident in a country or territory that is the subject or target of Sanctions, including, without limitation, Cuba, Iran, North Korea, Sudan, Syria, the following regions of Ukraine: Crimea, the Kherson, the Zaporizhzhia, the so-called Donetsk People’s Republic and the so-called Luhansk People’s Republic, and Venezuela (each, a “Sanctioned Country”); and the Company will not directly or indirectly use the proceeds of the offering of the Securities hereunder, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity (i) to fund or facilitate any activities of or business with any person that, at the time of such funding or facilitation, is the subject or target of Sanctions, (ii) to fund or facilitate any activities of or business in any Sanctioned Country or (iii) in any other manner that will result in a violation by any person (including any person participating in the transaction, whether as underwriter, initial purchaser, advisor, investor or otherwise) of Sanctions. For the past five years, the Company and its subsidiaries have not knowingly engaged in, and are not now knowingly engaged in any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any Sanctioned Country.

10

(hh) No Restrictions on Subsidiaries. No subsidiary of the Company is currently prohibited, directly or indirectly, under any agreement or other instrument to which it is a party or is subject, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock or similar ownership interest, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s properties or assets to the Company or any other subsidiary of the Company.

(ii) No Broker’s Fees. Neither the Company nor any of its subsidiaries is a party to any contract, agreement or understanding with any person (other than this Agreement) that would give rise to a valid claim against any of them or any Underwriter for a brokerage commission, finder’s fee or like payment in connection with the offering and sale of the Securities.

(jj) No Registration Rights. No person has the right to require the Company or any of its subsidiaries to register any securities for sale under the Securities Act by reason of the filing of the Registration Statement with the Commission or the issuance and sale of the Securities.

(kk) No Stabilization. The Company has not taken, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities.

(ll) Sarbanes-Oxley Act. There is and has been no failure on the part of the Company or any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the Sarbanes-Oxley Act of 2002, as amended, and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”), including Section 402 related to loans and Sections 302 and 906 related to certifications.

(mm) Cybersecurity. Except as disclosed in the Prospectus and the Disclosure Package, there has been no security breach or other compromise of or relating to any of the Company’s or its subsidiaries’ information technology and computer systems, networks, hardware, software, data (including the data of their respective customers, employees, suppliers and vendors and any third-party data maintained by or on behalf of them used in connection with their businesses) or equipment (collectively, “IT Systems and Data”), except as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. The Company and its subsidiaries have not been notified of, and have no knowledge of any event or condition that would reasonably be expected to result in, any security breach or other compromise to their IT Systems and Data, except as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. The Company and its subsidiaries are presently in compliance with all applicable laws and statutes, all judgments, orders, rules and regulations of any court or arbitrator or governmental or regulatory authority, all internal policies and all contractual obligations relating to the privacy and security of their IT Systems and Data and to the protection of such IT Systems and Data from unauthorized use, access, misappropriation or modification, except as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(nn) Status under the Securities Act. The Company is not an ineligible issuer and is a well-known seasoned issuer, in each case as defined under the Securities Act, in each case at the times specified in the Securities Act in connection with the offering of the Securities.

11

4. Further Agreements of the Company. The Company covenants and agrees with each Underwriter that:

(a) Required Filings. The Company will file the final Prospectus with the Commission within the time periods specified by Rule 424(b) under the Securities Act, will file any Issuer Free Writing Prospectus (including the Pricing Term Sheet referred to in Annex B hereto) to the extent required by Rule 433 under the Securities Act; and the Company will furnish copies of the Prospectus and each Issuer Free Writing Prospectus (to the extent not previously delivered) to the Underwriters in New York City prior to 10:00 A.M., New York City time, on the business day next succeeding the date of this Agreement in such quantities as the Representatives may reasonably request. The Company will pay the registration fees for this offering within the time period required by Rule 456(b)(1)(i) under the Securities Act (without giving effect to the proviso therein) and in any event prior to the Closing Date.

(b) Delivery of Copies. The Company will deliver, without charge, (i) to the Underwriters, the Registration Statement as originally filed and each amendment thereto, in each case including all exhibits and consents filed therewith and documents incorporated by reference therein; and (ii) during the Prospectus Delivery Period (as defined below), as many copies of the Prospectus (including all amendments and supplements thereto and documents incorporated by reference therein) and each Issuer Free Writing Prospectus as the Representatives may reasonably request. As used herein, the term “Prospectus Delivery Period” means such period of time after the first date of the public offering of the Securities as in the opinion of counsel for the Underwriters a prospectus relating to the Securities is required by law to be delivered (or required to be delivered but for Rule 172 under the Securities Act) in connection with sales of the Securities by any Underwriter or dealer.

(c) Amendments or Supplements; Issuer Free Writing Prospectuses. During the Prospectus Delivery Period, before making, preparing, using, authorizing, approving, referring to or filing any Issuer Free Writing Prospectus, and before filing any amendment or supplement to the Registration Statement or the Prospectus, the Company will furnish to the Representatives and counsel for the Underwriters a copy of the proposed Issuer Free Writing Prospectus, amendment or supplement for review and will not make, prepare, use, authorize, approve, refer to or file any such Issuer Free Writing Prospectus or file any such proposed amendment or supplement to which the Representatives reasonably objects.

(d) Notice to the Representatives. During the Prospectus Delivery Period, the Company will advise the Representatives promptly, and confirm such advice in writing, (i) when any amendment to the Registration Statement has been filed or becomes effective; (ii) when any supplement to the Prospectus or any amendment to the Prospectus or any Issuer Free Writing Prospectus has been filed; (iii) of any request by the Commission for any amendment to the Registration Statement or any amendment or supplement to the Prospectus or the receipt of any comments from the Commission relating to the Registration Statement or any other request by the Commission for any additional information relating to the Securities; (iv) of the issuance by the Commission of any order suspending the effectiveness of the Registration Statement or preventing or suspending the use of any Preliminary Prospectus, the Prospectus, any Pricing Disclosure Package or any Issuer Free Writing Prospectus or the initiation or threatening of any proceeding for that purpose or pursuant to Section 8A of the Securities Act; (v) of the occurrence of any event within the Prospectus Delivery Period as a result of which the Prospectus, any of the Pricing Disclosure Package or any Issuer Free Writing Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances existing when the Prospectus, the Pricing Disclosure Package or any such Issuer Free Writing Prospectus is delivered to a purchaser, not misleading; and (vi) of the receipt by the Company of any notice of objection of the Commission to the use of the Registration Statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act; and (vii) of the receipt by the Company of any notice with respect to any suspension of the qualification of the Securities for offer and sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and the Company will use its reasonable best efforts to prevent the issuance of any such order suspending the effectiveness of the Registration Statement, preventing or suspending the use of any Preliminary Prospectus, any of the Pricing Disclosure Package, Issuer Free Writing Prospectus or the Prospectus, or suspending any such qualification of the Securities and, if any such order is issued, will obtain as soon as possible the withdrawal thereof.

12

(e) Pricing Disclosure Package. If at any time prior to the Closing Date (i) any event shall occur or condition shall exist as a result of which any of the Pricing Disclosure Package as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading or (ii) it is necessary to amend or supplement the Pricing Disclosure Package to comply with law, the Company will promptly notify the Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission (to the extent required) and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Pricing Disclosure Package (or any document to be filed with the Commission and incorporated by reference therein) as may be necessary so that the statements in any of the Pricing Disclosure Package as so amended or supplemented (including such documents to be incorporated by reference therein) will not, in the light of the circumstances under which they were made, be misleading or so that any of the Pricing Disclosure Package will comply with law.

(f) Ongoing Compliance. If during the Prospectus Delivery Period (i) any event shall occur or condition shall exist as a result of which the Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances existing when the Prospectus is delivered to a purchaser, not misleading or (ii) it is necessary to amend or supplement the Prospectus to comply with law, the Company will promptly notify the Underwriters thereof and forthwith prepare and, subject to paragraph (c) above, file with the Commission and furnish to the Underwriters and to such dealers as the Representatives may designate, such amendments or supplements to the Prospectus (or any document to be filed with the Commission and incorporated by reference therein) as may be necessary so that the statements in the Prospectus as so amended or supplemented including such documents to be incorporated by reference therein will not, in the light of the circumstances existing when the Prospectus is delivered to a purchaser, be misleading or so that the Prospectus will comply with law.

(g) Blue Sky Compliance. The Company will take such actions as the Representatives reasonably request to qualify the Securities for offer and sale under the securities or Blue Sky laws of such jurisdictions as the Representatives shall reasonably request and will continue such qualifications in effect so long as required for distribution of the Securities; provided that the Company shall not be required to (i) qualify as a foreign corporation or other entity or as a dealer in securities in any such jurisdiction where it would not otherwise be required to so qualify, (ii) file any general consent to service of process in any such jurisdiction or (iii) subject itself to taxation in any such jurisdiction if it is not otherwise so subject.

(h) Earning Statement. The Company will make generally available to its security holders and the Representatives as soon as practicable an earning statement that satisfies the provisions of Section 11(a) of the Securities Act and Rule 158 of the Commission promulgated thereunder covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the “effective date” (as defined in Rule 158) of the Registration Statement.

(i) Clear Market. During the period from the date hereof through and including the Closing Date, the Company will not, without the prior written consent of the Representatives, offer, sell, contract to sell or otherwise dispose of any debt securities issued or guaranteed by the Company and having a tenor of more than one year.

13

(j) Use of Proceeds. The Company will apply the net proceeds from the sale of the Securities as described in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus under the heading “Use of Proceeds”.

(k) DTC. The Company will assist the Underwriters in arranging for the Securities to be eligible for clearance and settlement through DTC.

(l) No Stabilization. The Company will not take, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Securities.

(m) Record Retention. The Company will, pursuant to reasonable procedures developed in good faith, retain copies of each Issuer Free Writing Prospectus that is not filed with the Commission in accordance with Rule 433 under the Securities Act.

5. Certain Agreements of the Underwriters. Each Underwriter hereby represents and agrees that:

(a) It has not and will not use, authorize use of, refer to, or participate in the planning for use of, any “free writing prospectus”, as defined in Rule 405 under the Securities Act (which term includes use of any written information furnished to the Commission by the Company and not incorporated by reference into the Registration Statement and any press release issued by the Company) other than (i) a free writing prospectus that, solely as a result of use by such Underwriter, would not trigger an obligation to file such free writing prospectus with the Commission pursuant to Rule 433, (ii) any Issuer Free Writing Prospectus listed on Annex A or prepared pursuant to Section 3(c) or Section 4(c) above (including any electronic road show), or (iii) any free writing prospectus prepared by such Underwriter and approved by the Company in advance in writing (each such free writing prospectus referred to in clauses (i) or (iii), an “Underwriter Free Writing Prospectus”). Notwithstanding the foregoing, the Underwriters may use the Pricing Term Sheet referred to in Annex B hereto without the consent of the Company.

(b) It is not subject to any pending proceeding under Section 8A of the Securities Act with respect to the offering (and will promptly notify the Company if any such proceeding against it is initiated during the Prospectus Delivery Period).

6. Conditions of Underwriters’ Obligations. The obligation of each Underwriter to purchase Securities on the Closing Date as provided herein is subject to the performance by the Company of its covenants and other obligations hereunder and to the following additional conditions:

(a) Registration Compliance; No Stop Order. No order suspending the effectiveness of the Registration Statement shall be in effect, and no proceeding for such purpose, pursuant to Rule 401(g)(2) or pursuant to Section 8A under the Securities Act shall be pending before or threatened by the Commission; the Prospectus and each Issuer Free Writing Prospectus shall have been timely filed with the Commission under the Securities Act (in the case of an Issuer Free Writing Prospectus, to the extent required by Rule 433 under the Securities Act) and in accordance with Section 4(a) hereof; and all requests by the Commission for additional information shall have been complied with to the reasonable satisfaction of the Representatives.

(b) Representations and Warranties. The representations and warranties of the Company contained herein shall be true and correct on the date hereof and on and as of the Closing Date; and the statements of the Company and its officers made in any certificates delivered pursuant to this Agreement shall be true and correct on and as of the Closing Date.

14

(c) No Downgrade. Subsequent to the earlier of (A) the Applicable Time and (B) the execution and delivery of this Agreement, (i) no downgrading shall have occurred in the rating accorded the Securities or any other debt securities or preferred stock issued or guaranteed by the Company or any of its subsidiaries by any “nationally recognized statistical rating organization,” as such term is defined under Section 3(a)(62) under the Exchange Act and (ii) no such organization shall have publicly announced that it has under surveillance or review, or has changed its outlook with respect to, its rating of the Securities or of any other debt securities or preferred stock issued or guaranteed by the Company or any of its subsidiaries (other than an announcement with positive implications of a possible upgrading).

(d) No Material Adverse Change. No event or condition of a type described in Section 3(g) hereof shall have occurred or shall exist, which event or condition is not described in each of the Pricing Disclosure Package (excluding any amendment or supplement thereto) and the Prospectus (excluding any amendment or supplement thereto) the effect of which in the judgment of the Representatives makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated by this Agreement, the Pricing Disclosure Package and the Prospectus.

(e) Officer’s Certificate. The Representatives shall have received on and as of the Closing Date a certificate of an executive officer of the Company who has specific knowledge of the Company’s financial matters and is satisfactory to the Representatives (i) confirming that such officer has carefully reviewed the Registration Statement, the Pricing Disclosure Package and the Prospectus and, to the knowledge of such officer, the representations set forth in Sections 3(b) and 3(d) hereof are true and correct, (ii) confirming that the other representations and warranties of the Company in this Agreement are true and correct and that the Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date and (iii) to the effect set forth in paragraphs (a), (c) and (d) above.

(f) Comfort Letters. On the date of this Agreement and on the Closing Date, PricewaterhouseCoopers, LLP shall have furnished to the Representatives, at the request of the Company, letters, dated the respective dates of delivery thereof and addressed to the Underwriters, in form and substance reasonably satisfactory to the Representatives, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained or incorporated by reference in each of the Registration Statement, the Pricing Disclosure Package and the Prospectus; provided that the letter delivered on the Closing Date shall use a “cut-off” date no more than three business days prior to the Closing Date

(g) Opinion Letters and 10b-5 Statement of Counsels for the Company. The Representatives shall have received on and as of the Closing Date (i) opinion letters, dated the Closing Date and addressed to the Underwriters, of Skadden, Arps, Slate, Meagher & Flom LLP, counsel for the Company and (ii) an opinion letter and 10b-5 statement, dated the Closing Date and addressed to the Underwriters, of GableGotwals, counsel for the Company, each in the form and substance reasonably satisfactory to the Representatives.

(h) Opinion Letter and 10b-5 Statement of Counsel for the Underwriters. The Representatives shall have received on and as of the Closing Date an opinion letter and 10b-5 statement, addressed to the Underwriters, of Hunton Andrews Kurth, LLP, counsel for the Underwriters, with respect to such matters as the Representatives may reasonably request, and such counsel shall have received such documents and information as they may reasonably request to enable them to pass upon such matters.

15

(i) No Legal Impediment to Issuance. No action shall have been taken and no statute, rule, regulation or order shall have been enacted, adopted or issued by any federal, state or foreign governmental or regulatory authority that would, as of the Closing Date, prevent the issuance or sale of the Securities; and no injunction or order of any federal, state or foreign court shall have been issued that would, as of the Closing Date, prevent the issuance or sale of the Securities.

(j) Good Standing. The Representatives shall have received on and as of the Closing Date satisfactory evidence of the good standing of the Company in Oklahoma, Kansas and Texas and its subsidiaries in their respective jurisdictions of organization, from the appropriate governmental authorities of such jurisdictions.

(k) DTC. The Securities shall be eligible for clearance and settlement through DTC.

(l) Indenture and Securities. The Indenture shall have been duly executed and delivered by a duly authorized officer of the Company and the Trustee, and the Securities shall have been duly executed and delivered by a duly authorized officer of the Company and duly authenticated by the Trustee.

(m) Additional Documents. On or prior to the Closing Date, the Company shall have furnished to the Representatives such further certificates and documents as the Representatives may reasonably request.

All opinions, letters, certificates and evidence mentioned above or elsewhere in this Agreement shall be deemed to be in compliance with the provisions hereof only if they are in form and substance reasonably satisfactory to counsel for the Underwriters.

7. Indemnification and Contribution.

(a) Indemnification of the Underwriters. The Company agrees to indemnify and hold harmless each Underwriter, and each of their respective affiliates (within the meaning of Rule 405 under the Securities Act), directors and officers and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities (including, without limitation, legal fees and other expenses incurred in connection with any suit, action or proceeding or any claim asserted, as such fees and expenses are incurred), joint or several, that arise out of, or are based upon, (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary in order to make the statements therein, not misleading, or (ii) any untrue statement or alleged untrue statement of a material fact contained in the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Pricing Disclosure Package, or caused by any omission or alleged omission to state therein a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, in each case except insofar as such losses, claims, damages or liabilities arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any Underwriter Information.

16

(b) Indemnification of the Company. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, its directors and officers and each person, if any, who controls the Company within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the indemnity set forth in paragraph (a) above, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to such Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in the Registration Statement, the Prospectus (or any amendment or supplement thereto), any Issuer Free Writing Prospectus or any Pricing Disclosure Package, it being understood and agreed that the only such information consists of the following paragraphs in the Preliminary Prospectus and the Prospectus (collectively, the “Underwriter Information”): the information in under the heading “Underwriting (Conflicts of Interest)” in (A) the third sentence of the third paragraph related to the Underwriters’ market making activities, (B) the first sentence of the fourth paragraph related to discounts, (C) the sixth, seventh and eighth paragraphs related to over-allotment, stabilization, syndicate covering transactions and penalty bids and (D) the first sentence of the ninth paragraph and the tenth and eleventh paragraphs relating to certain relations among the Company and the Underwriters.

(c) Notice and Procedures. If any suit, action, proceeding (including any governmental or regulatory investigation), claim or demand shall be brought or asserted against any person in respect of which indemnification may be sought pursuant to either paragraph (a) or (b) above, such person (the “Indemnified Person”) shall promptly notify the person against whom such indemnification may be sought (the “Indemnifying Person”) in writing; provided that the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have under paragraph (a) or (b) above except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided, further, that the failure to notify the Indemnifying Person shall not relieve it from any liability that it may have to an Indemnified Person otherwise than under paragraph (a) or (b) above. If any such proceeding shall be brought or asserted against an Indemnified Person and it shall have notified the Indemnifying Person thereof, the Indemnifying Person shall retain counsel reasonably satisfactory to the Indemnified Person (who shall not, without the consent of the Indemnified Person, be counsel to the Indemnifying Person) to represent the Indemnified Person and any others entitled to indemnification pursuant to this Section 7 that the Indemnifying Person may designate in such proceeding and shall pay the fees and expenses of such proceeding and shall pay the fees and expenses of such counsel related to such proceeding, as incurred. In any such proceeding, any Indemnified Person shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such Indemnified Person unless (i) the Indemnifying Person and the Indemnified Person shall have mutually agreed to the contrary; (ii) the Indemnifying Person has failed within a reasonable time to retain counsel reasonably satisfactory to the Indemnified Person; (iii) the Indemnified Person shall have reasonably concluded that there may be legal defenses available to it that are different from or in addition to those available to the Indemnifying Person; or (iv) the named parties in any such proceeding (including any impleaded parties) include both the Indemnifying Person and the Indemnified Person, and the Indemnified Person shall have reasonably concluded that representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood and agreed that the Indemnifying Person shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the fees and expenses of more than one separate firm (in addition to any local counsel) for all Indemnified Persons, and that all such fees and expenses shall be paid or reimbursed as they are incurred. Any such separate firm for any Underwriter, its affiliates, directors and officers and any control persons of such Underwriter shall be designated in writing by the Representatives and any such separate firm for the Company, its directors and officers who signed the Registration Statement and any control persons of the Company shall be designated in writing by the Company. The Indemnifying Person shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the Indemnifying Person agrees to indemnify each Indemnified Person from and against any loss

17

or liability by reason of such settlement or judgment. No Indemnifying Person shall, without the written consent of the Indemnified Person, effect any settlement of any pending or threatened proceeding in respect of which any Indemnified Person is or could have been a party and indemnification could have been sought hereunder by such Indemnified Person, unless such settlement (x) includes an unconditional release of such Indemnified Person, in form and substance reasonably satisfactory to such Indemnified Person, from all liability on claims that are the subject matter of such proceeding and (y) does not include any statement as to or any admission of fault, culpability or a failure to act by or on behalf of any Indemnified Person.

(d) Contribution. If the indemnification provided for in paragraph (a) or (b) above is unavailable to an Indemnified Person or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each Indemnifying Person under such paragraph, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Securities or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same respective proportions as the net proceeds (before deducting expenses) received by the Company from the sale of the Securities and the total underwriting discounts and commissions received by the Underwriters in connection therewith, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate offering price of the Securities. The relative fault of the Company on the one hand and the Underwriters on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(e) Limitation on Liability. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 7 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in paragraph (d) above. The amount paid or payable by an Indemnified Person as a result of the losses, claims, damages and liabilities referred to in paragraph (d) above shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such Indemnified Person in connection with any such action or claim. Notwithstanding the provisions of this Section 7, in no event shall an Underwriter be required to contribute any amount in excess of the amount by which the total underwriting discounts and commissions received by such Underwriter with respect to the offering of the Securities exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 7 are several in proportion to their respective purchase obligations hereunder and not joint.

(f) Non-Exclusive Remedies. The remedies provided for in this Section 7 are not exclusive and shall not limit any rights or remedies that may otherwise be available to any Indemnified Person at law or in equity.

18

8. Effectiveness of Agreement. This Agreement shall become effective as of the date first written above.

9. Termination. This Agreement may be terminated in the absolute discretion of the Representatives, by notice to the Company, if after the execution and delivery of this Agreement and on or prior to the Closing Date (i) trading generally shall have been suspended or materially limited on the New York Stock Exchange or the over-the-counter market; (ii) trading of any securities issued or guaranteed by the Company shall have been suspended on any exchange or in any over-the-counter market; (iii) a general moratorium on commercial banking activities shall have been declared by federal or New York State authorities; or (iv) there shall have occurred any outbreak or escalation of hostilities or any change in financial markets or any calamity or crisis, either within or outside the United States, that, in the judgment of the Representatives, is material and adverse and makes it impracticable or inadvisable to proceed with the offering, sale or delivery of the Securities on the terms and in the manner contemplated by this Agreement, the Pricing Disclosure Package and the Prospectus.

10. Defaulting Underwriter.

(a) If, on the Closing Date, any Underwriter defaults on its obligation to purchase the Securities that it has agreed to purchase hereunder, the non-defaulting Underwriters may in their discretion arrange for the purchase of such Securities by other persons satisfactory to the Company on the terms contained in this Agreement. If, within 36 hours after any such default by any Underwriter, the non-defaulting Underwriters do not arrange for the purchase of such Securities, then the Company shall be entitled to a further period of 36 hours within which to procure other persons satisfactory to the non-defaulting Underwriters to purchase such Securities on such terms. If other persons become obligated or agree to purchase the Securities of a defaulting Underwriter, either the non-defaulting Underwriters or the Company may postpone the Closing Date for up to five full business days in order to effect any changes that in the opinion of counsel for the Company or counsel for the Underwriters may be necessary in the Registration Statement, the Pricing Disclosure Package and the Prospectus or in any other document or arrangement, and the Company agrees to promptly prepare any amendment or supplement to the Registration Statement, the Pricing Disclosure Package and the Prospectus that effects any such changes. As used in this Agreement, the term “Underwriter” includes, for all purposes of this Agreement unless the context otherwise requires, any person not listed in Schedule 1 hereto that, pursuant to this Section 10, purchases Securities that a defaulting Underwriter agreed but failed to purchase.

(b) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company as provided in paragraph (a) above, the aggregate principal amount of such Securities that remains unpurchased does not exceed one-eleventh of the aggregate principal amount of all the Securities, then the Company shall have the right to require each non-defaulting Underwriter to purchase the principal amount of Securities that such Underwriter agreed to purchase hereunder plus such Underwriter’s pro rata share (based on the principal amount of Securities that such Underwriter agreed to purchase hereunder) of the Securities of such defaulting Underwriter or Underwriters for which such arrangements have not been made.

(c) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Underwriter or Underwriters by the non-defaulting Underwriters and the Company as provided in paragraph (a) above, the aggregate principal amount of such Securities that remains unpurchased exceeds one-eleventh of the aggregate principal amount of all the Securities, or if the Company shall not exercise the right described in paragraph (b) above, then this Agreement shall terminate without liability on the part of the non-defaulting Underwriters. Any termination of this Agreement pursuant to this Section 10 shall be without liability on the part of the Company, except that the Company will continue to be liable for the payment of expenses as set forth in Section 11 hereof and except that the provisions of Section 7 hereof shall not terminate and shall remain in effect.

19

(d) Nothing contained herein shall relieve a defaulting Underwriter of any liability it may have to the Company or any non-defaulting Underwriter for damages caused by its default.

11. Payment of Expenses.

(a) Whether or not the transactions contemplated by this Agreement are consummated or this Agreement is terminated, the Company agrees to pay or cause to be paid all costs and expenses incident to the performance of its obligations hereunder, including without limitation, (i) the costs incident to the authorization, issuance, sale, preparation and delivery of the Securities and any taxes payable in that connection; (ii) the costs incident to the preparation, printing and filing under the Securities Act of the Registration Statement, the Preliminary Prospectus, any Issuer Free Writing Prospectus, any Pricing Disclosure Package and the Prospectus (including all exhibits, amendments and supplements thereto) and the distribution thereof; (iii) the costs of reproducing and distributing each of the Transaction Documents; (iv) the fees and expenses of the Company’s counsel and independent accountants; (v) the fees and expenses incurred in connection with the registration or qualification and determination of eligibility for investment of the Securities under the laws of such jurisdictions as the Representatives may designate and the preparation, printing and distribution of a Blue Sky Memorandum, but specifically excluding the related fees and expenses of counsel for the Underwriters; (vi) any fees charged by rating agencies for rating the Securities; (vii) the fees and expenses of the Trustee and any paying agent (including related fees and expenses of any counsel to such parties) and (viii) all expenses and application fees incurred in connection with any filing with, and clearance of the offering by, the Financial Industry Regulatory Authority, and the approval of the Securities for book-entry transfer by DTC. Notwithstanding the foregoing, except as expressly agreed otherwise in this Agreement, it is understood and agreed that the Underwriters will pay all fees and expenses of counsel to the Underwriters.

(b) If (i) this Agreement is terminated pursuant to Section 9, (ii) the Company for any reason fails to tender the Securities for delivery to the Underwriters or (iii) the Underwriters decline to purchase the Securities for any reason permitted under this Agreement, the Company agrees to reimburse the Underwriters for all out-of-pocket costs and expenses (including the fees and expenses of their counsel) reasonably incurred by the Underwriters in connection with this Agreement and the offering contemplated hereby.

12. Persons Entitled to Benefit of Agreement. This Agreement shall inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and any controlling persons referred to herein, and the affiliates of each Underwriter referred to in Section 7 hereof. Nothing in this Agreement is intended or shall be construed to give any other person any legal or equitable right, remedy or claim under or in respect of this Agreement or any provision contained herein. No purchaser of Securities from any Underwriter shall be deemed to be a successor merely by reason of such purchase.

13. Survival. The respective indemnities, rights of contribution, representations, warranties and agreements of the Company and the Underwriters contained in this Agreement or made by or on behalf of the Company or the Underwriters pursuant to this Agreement or any certificate delivered pursuant hereto shall survive the delivery of and payment for the Securities and shall remain in full force and effect, regardless of any termination of this Agreement or any investigation made by or on behalf of the Company or the Underwriters.

20

14. Certain Defined Terms. For purposes of this Agreement, (a) except where otherwise expressly provided, the term “affiliate” has the meaning set forth in Rule 405 under the Securities Act; (b) the term “business day” means any day other than a day on which banks are permitted or required to be closed in New York City; and (c) the term “subsidiary” has the meaning set forth in Rule 405 under the Securities Act; and (d) the term “significant subsidiary” has the meaning set forth in Rule 1-02 of Regulation S-X under the Exchange Act.

15. Compliance with USA Patriot Act. In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients.

16. Miscellaneous.

(a) Authority of the Representatives. Any action by the Underwriters hereunder may be taken by the Representatives on behalf of the Underwriters, and any such action taken by the Representatives shall be binding upon the Underwriters.

(b) Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly given if mailed or transmitted and confirmed by any standard form of telecommunication. Notices to the Underwriters shall be given to J.P. Morgan Securities LLC, 383 Madison Avenue, New York, New York 10179, Attention: Investment Grade Syndicate Desk, 3rd Floor, Fax No. (212) 834-6081, Mizuho Securities USA LLC, 1271 Avenue of the Americas, New York, New York 10020, Attention: Debt Capital Markets, Fax No.: (212) 205-7812 and U.S. Bancorp Investments, Inc., 214 North Tryon Street, 26th Floor, Charlotte, North Carolina 28202, Attention: Investment Grade Syndicate, Fax No.: (704) 335-2393. Notices to the Company shall be given to it at 15 East Fifth Street, Tulsa, Oklahoma 74103, (fax: 918-947-6117); Attention: General Counsel.

(c) Governing Law. This Agreement and any claim, controversy or dispute arising under or related to this Agreement shall be governed by and construed in accordance with the laws of the State of New York.

(d) Submission to Jurisdiction. The parties hereto hereby submit to the jurisdiction of the U.S. federal and New York state courts in the Borough of Manhattan in The City of New York in any suit or proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. The Company waives any objection which it may now or hereafter have to the laying of venue of any such suit or proceeding in such courts. The Company agrees that final judgment in any such suit, action or proceeding brought in such court shall be conclusive and binding upon the Company and may be enforced in any court to the jurisdiction of which Company is subject by a suit upon such judgment. The Company irrevocably appoints National Registered Agents, Inc., located 111 Eighth Avenue – 13^th Floor, New York, New York 10011, as its authorized agent in the Borough of Manhattan in The City of New York upon which process may be served in any such suit or proceeding, and agrees that service of process upon such authorized agent, and written notice of such service to the Company by the person serving the same to the address provided in this Section 16, shall be deemed in every respect effective service of process upon the Company in any such suit or proceeding.

(e) Waiver of Jury Trial. Each of the parties hereto hereby waives any right to trial by jury in any suit or proceeding arising out of or relating to this Agreement.

21

(f) Counterparts. This Agreement may be signed in counterparts (which may include counterparts delivered by any standard form of telecommunication), each of which shall be an original and all of which together shall constitute one and the same instrument. Delivery of an executed signature page of this Agreement by facsimile or any other rapid transmission device designed to produce a written record of the communication transmitted shall be as effective as delivery of a manually executed counterpart thereof.

The words “execution,” “executed,” “signed,” signature,” and words of like import in this Agreement or in any other certificate, agreement or document related to this Agreement shall include images of manually executed signatures transmitted by facsimile, email or other electronic format (including, without limitation, “pdf,” “tif” or “jpg”) and other electronic signatures (including, without limitation, AdobeSign). The use of electronic signatures and electronic records (including, without limitation, any contract or other record created, generated, sent, communicated, received, or stored by electronic means) shall be of the same legal effect, validity and enforceability as a manually executed signature or use of a paper-based record-keeping system to the fullest extent permitted by applicable law, including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act and any other applicable law, including, without limitation, any state law based on the Uniform Electronic Transactions Act or the Uniform Commercial Code.

(g) Amendments or Waivers. No amendment or waiver of any provision of this Agreement, nor any consent or approval to any departure therefrom, shall in any event be effective unless the same shall be in writing and signed by the parties hereto.

(h) Headings. The headings herein are included for convenience of reference only and are not intended to be part of, or to affect the meaning or interpretation of, this Agreement.

17. Recognition of the U.S. Special Resolution Regimes.

(a) In the event that an Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special Resolution Regime, the transfer from such party that is a Covered Entity of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent as the transfer would be effective under the U.S. Special Resolution Regime if this Agreement, and any such interest and obligation, were governed by the laws of the United States or a state of the United States.

(b) In the event that an Underwriter is a Covered Entity or a BHC Act Affiliate of the Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special Resolution Regime, any Default Rights under this Agreement that may be exercised against such party that is a Covered Entity are permitted to be exercised to no greater extent than such Default Rights could be exercised under the U.S. Special Resolution Regime if this Agreement were governed by the laws of the United States or a state of the United States.

For purposes of this Section 17 a “BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k) or 1813(w), as applicable. “Covered Entity” means any of the following: (i) a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b); (ii) a “covered bank” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or (iii) a “covered FSI” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b). “Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable. “U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

22

If the foregoing is in accordance with your understanding, please indicate your acceptance of this Agreement by signing in the space provided below.

Accepted: As of the date first written above

As Representatives of the several Underwriters listed in Schedule 1 hereto.

[Signature Page to Underwriting Agreement]

Schedule 1

Annex A

Pricing Disclosure Package

Annex B

Filed Pursuant to Rule 433

Registration Statement No. 333-269966

Pricing Term Sheet

ONE GAS, INC.

Pricing Term Sheet

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it from J.P. Morgan Securities LLC by calling collect at 1-212-834-4533, Mizuho Securities USA LLC by calling toll-free at 1-866-271-7403 or U.S. Bancorp Investments, Inc. by calling toll-free at 1-877-558-2607.

Pricing Term Sheet dated December 11, 2023 to the Preliminary Prospectus Supplement dated December 11, 2023, and the accompanying Prospectus dated February 23, 2023 (together, the “Preliminary Prospectus”) of ONE Gas, Inc. The information in this Pricing Term Sheet supplements the Preliminary Prospectus and supersedes the information in the Preliminary Prospectus to the extent it is inconsistent with the information in the Preliminary Prospectus. This Pricing Term Sheet is qualified in its entirety by reference to the Preliminary Prospectus. Financial information presented in the Preliminary Prospectus is deemed to have changed to the extent affected by the changes described herein. This Pricing Term Sheet should be read together with the Preliminary Prospectus, including the documents incorporated by reference therein, before making a decision in connection with an investment in the securities. Capitalized terms used in this Pricing Term Sheet but not defined have the meanings given them in the Preliminary Prospectus.

Exhibit 4.2

ONE GAS, INC.

SUPPLEMENTAL INDENTURE NO. 7

$300,000,000 5.10% Senior Notes due 2029

THIS SUPPLEMENTAL INDENTURE NO. 7, dated as of December 13, 2023 (this “Supplemental Indenture”), between ONE GAS, INC., an Oklahoma corporation (the “Company”), and U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION (successor in interest to U.S. Bank National Association), a national banking association, as trustee (the “Trustee”).

RECITALS OF THE COMPANY:

WHEREAS, the Company has heretofore executed and delivered to the Trustee an Indenture, dated as of January 27, 2014 (the “Original Indenture”) (the Original Indenture, as amended and supplemented from time to time, including, without limitation, pursuant to this Supplemental Indenture, being referred to herein collectively as the “Indenture”), providing for the issuance from time to time of one or more series of Securities (as defined in the Original Indenture);

WHEREAS, Article Nine of the Original Indenture provides for various matters with respect to any series of Securities issued under the Indenture to be established in an indenture supplemental to the Original Indenture;

WHEREAS, Section 9.1(7) of the Original Indenture provides that the Company and the Trustee may enter into an indenture supplemental to the Original Indenture to establish the form or terms of Securities of any series as permitted by Sections 2.1 and 3.1 of the Original Indenture; and

WHEREAS, all the conditions and requirements necessary to make this Supplemental Indenture, when duly executed and delivered, a valid and binding agreement in accordance with its terms and for the purposes herein expressed, have been performed and fulfilled.

NOW THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH

For and in consideration of the premises and the issuance of the series of Securities provided for herein, the Company and the Trustee mutually covenant and agree for the equal and proportionate benefit of the respective Holders of the Securities of each such series as follows:

ARTICLE I

RELATION TO INDENTURE; DEFINITIONS; RULES OF CONSTRUCTION

SECTION 1.1 Relation to Indenture. This Supplemental Indenture constitutes an integral part of the Indenture.

SECTION 1.2 Definitions. For all purposes of this Supplemental Indenture, the following terms shall have the respective meanings set forth in this Section.

“Definitive Note” means a certificated Note that does not include the legend prescribed in Section 2.4 of the Original Indenture.

“Depository” means The Depository Trust Company, its nominees and their respective successors.

“Global Notes” means one or more Securities evidencing all or part of the Securities to be issued as Book-Entry Securities, issued to the Depositary in accordance with Section 3.1 of the Original Indenture and bearing the legend prescribed in Section 2.4 of the Original Indenture.

“Notes” shall have the meaning set forth in Section 2.1 hereof.

“Notes Custodian” means the custodian with respect to a Global Note (as appointed by the Depository) or any successor person thereto, who will initially be the Trustee.

“Participant” means members of, or participants in, the Depository.

SECTION 1.3 Rules of Construction. For all purposes of this Supplemental Indenture:

(a) capitalized terms used herein without definition shall have the meanings assigned thereto in the Original Indenture;

(b) all references herein to Articles and Sections, unless otherwise specified, refer to the corresponding Articles and Sections of this Supplemental Indenture;

(c) terms “herein,” “hereof,” “hereunder” and other words of similar import refer to this Supplemental Indenture; and

(d) in the event of a conflict with the definition of terms in the Original Indenture, the definitions in this Supplemental Indenture shall control.

ARTICLE II

THE SECURITIES

SECTION 2.1 Title of the Notes. There shall be a series of Securities designated the 5.10% Senior Notes due April 1, 2029.

SECTION 2.2 Initial Principal Amount. The Notes will be initially issued in an aggregate principal amount of $300,000,000.

SECTION 2.3 Form and Dating.

(a) General. The Notes and the Trustee’s certificate of authentication shall be substantially in the form of Exhibit A hereto. The Notes may have notations, legends or endorsements required by law, stock exchange rule or usage. Each Note shall be dated the date of its authentication. The Notes shall be in denominations of $2,000 and integral multiples of $1,000 in excess thereof.

2

The terms and provisions contained in the Notes shall constitute, and are hereby expressly made, a part of this Supplemental Indenture, and the Company and the Trustee, by their execution and delivery of this Supplemental Indenture, expressly agree to such terms and provisions and to be bound thereby. However, to the extent any provision of the Notes conflicts with the express provisions of this Supplemental Indenture, the provisions of this Supplemental Indenture shall govern and be controlling.

The Company hereby designates The Depository Trust Company as the initial depository for the Global Notes.

(b) Global Notes. The Notes shall initially be issuable in whole or in part in the form of one or more Global Notes. Such Global Notes (i) shall be deposited with, or on behalf of, the Depository, which shall act as depository with respect to the Notes, (ii) shall bear the legend prescribed by Section 2.4 of the Original Indenture, (iii) may be exchanged in whole or in part upon the terms and subject to the conditions provided in Section 3.5 of the Original Indenture and (iv) shall otherwise be subject to the applicable provisions of the Indenture.

(c) Book-Entry Provisions. This Section 2.3(c) shall apply only to a Global Note deposited with or on behalf of the Depository. The Company shall execute and the Trustee shall, in accordance with this Section 2.3(c) and pursuant to a Company Order, authenticate and deliver initially one or more Global Notes that (a) shall be registered in the name of the Depository for such Global Note or Global Notes or the nominee of such Depository and (b) shall be delivered by the Trustee to such Depository or pursuant to such Depository’s instructions or held by the Trustee as Notes Custodian.

Participants shall have no rights under the Indenture with respect to any Global Note held on their behalf by the Depository or by the Trustee as Notes Custodian or under such Global Note, and the Depository may be treated by the Company, the Trustee and any agent of the Company or the Trustee as the absolute owner of such Global Note for all purposes whatsoever. Notwithstanding the foregoing, nothing herein shall prevent the Company, the Trustee or any agent of the Company or the Trustee from giving effect to any written certification, proxy or other authorization furnished by the Depository or impair, as between the Depository and its Participants, the operation of customary practices of such Depository governing the exercise of the rights of a holder of a beneficial interest in any Global Note.

(d) Definitive Notes. Except as provided in Section 2.4 hereof, owners of beneficial interests in Global Notes will not be entitled to receive physical delivery of certificated Notes.

(e) Cancellation of Global Note. At such time as all beneficial interests in a Global Note have either been exchanged for Definitive Notes, transferred, redeemed, repurchased or canceled, such Global Note shall be returned by the Depository to the Trustee for cancellation or retained and canceled by the Trustee. At any time prior to such cancellation, if any beneficial interest in a Global Note is exchanged for Definitive Notes, transferred in exchange for an interest in another Global Note, redeemed, repurchased or canceled, the principal amount of Notes represented by such Global Note shall be reduced and an adjustment shall be made on the books and records of the Trustee (if it is then the Notes Custodian for such Global Note) with respect to such Global Note, by the Trustee or the Notes Custodian, to reflect such reduction.

3

SECTION 2.4 Definitive Notes.

(a) A Global Note deposited with the Depository or with the Trustee as Notes Custodian pursuant to Section 2.3 shall be transferred to the beneficial owners thereof in the form of Definitive Notes in an aggregate principal amount equal to the principal amount of such Global Note, in exchange for such Global Note in the event (i) the Depository (A) notifies the Company that the Depository is no longer willing or able to act as a depositary or clearing system for the Notes or (B) ceases to be a “clearing agency” registered under the Securities Exchange Act of 1934, as amended, and, in either event, a successor depositary or clearing system is not appointed by the Company within 90 days of such notice or cessation, (ii) the Company, in its sole discretion, notifies the Trustee in writing that it elects to cause the issuance of Definitive Notes under the Indenture, or (iii) upon the occurrence and continuation of an Event of Default and the Depository notifies the Trustee of its decision to exchange the Global Note for Definitive Notes.

(b) Any Global Note that is transferable to the beneficial owners thereof pursuant to this Section 2.4 shall be surrendered by the Depository to the Trustee, to be so transferred, in whole or from time to time in part, without charge, and upon Company Order the Trustee shall authenticate and deliver, upon such transfer of each portion of such Global Note, an equal aggregate principal amount of Definitive Notes of authorized denominations. Any portion of a Global Note transferred pursuant to this Section 2.4 shall be executed, authenticated and delivered only in denominations of $2,000 of principal amount and any integral multiple of $1,000 in excess thereof and registered in such names as the Depository shall direct.

(c) The registered Holder of a Global Note may grant proxies and otherwise authorize any Person, including Participants and Persons that may hold interests through Participants, to take any action which a Holder is entitled to take under the Indenture or the Notes as provided therein.

(d) In the event of the occurrence of any of the events specified in Section 2.4(a)(i), (ii) or (iii), the Company will promptly make available to the Trustee a reasonable supply of Definitive Notes in fully registered form without interest coupons.

SECTION 2.5 Stated Maturity. The Stated Maturity of the Notes shall be April 1, 2029.

SECTION 2.6 Interest and Interest Rate. The rate at which the Notes shall bear interest, the date or dates from which such interest shall accrue, the interest payment dates on which any such interest shall be payable and the regular record date for any interest payable on any interest payment date, in each case, shall be as set forth in the form of Note set forth as Exhibit A hereto.

SECTION 2.7 Optional Redemption. At its option, the Company may redeem the Notes, in whole or in part, at any time and from time to time, at the applicable redemption price determined as set forth in the form of Note attached hereto as Exhibit A, in accordance with the terms set forth therein and in accordance with Article XI of the Original Indenture.

4

ARTICLE III

MISCELLANEOUS PROVISIONS

SECTION 3.1 Ratification. The Original Indenture, as amended and supplemented from time to time, including ,without limitation, as supplemented and amended by this Supplemental Indenture, is in all respects hereby adopted, ratified and confirmed.

SECTION 3.2 Counterparts. This Supplemental Indenture may be executed in any number of counterparts, each of which when so executed shall be deemed an original, and all such counterparts shall together constitute but one and the same instrument.

SECTION 3.3 Governing Law. THIS SUPPLEMENTAL INDENTURE AND EACH SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

SECTION 3.4 Conflict with Trust Indenture Act. If any provision hereof limits, qualifies or conflicts with a provision of the Trust Indenture Act that is required under such Act to be a part of and govern this Supplemental Indenture, the latter provision shall control. If any provision of this Supplemental Indenture modifies or excludes any provision of the Trust Indenture Act that may be so modified or excluded, the latter provision shall be deemed to apply to this Supplemental Indenture as so modified or to be excluded, as the case may be.

[Signature Page Follows]

5

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture No. 7 to be duly executed as of the day and year first above written.

[SIGNATURE PAGE TO SUPPLEMENTAL INDENTURE NO. 7]

[SIGNATURE PAGE TO SUPPLEMENTAL INDENTURE NO. 7]

Exhibit A

[FORM FACE OF NOTE]

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

ONE GAS, INC.

5.10% Senior Notes due 2029

ONE Gas, Inc., a corporation duly organized and existing under the laws of Oklahoma (herein called the “Company,” which term includes any successor Person under the Indenture hereinafter referred to), for value received, hereby promises to pay to, or registered assigns, the principal sum of [    ], as such amount may be increased or decreased as set forth in the Schedule of Increase or Decrease in Principal Amount of Global Note attached hereto, on April 1, 2029, the maturity date, and to pay interest thereon from December 13, 2023 or from the most recent Interest Payment Date (as defined below) to which interest has been paid or duly provided for, semi-annually on April 1 and October 1 (each such date, an “Interest Payment Date”) and in each year, commencing April 1, 2024, at the rate of 5.10% per annum, until the principal hereof is paid or made available for payment, and (to the extent that the payment of such interest shall be legally enforceable) at the same rate on any overdue principal and premium and on any overdue installment of interest. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date (as defined below) for such interest, which shall be (a) the 15^th of March or 15^th of September (whether or not a Business Day), as the case may be, immediately preceding such Interest Payment Date or (b) so long as this note is a global note in book-entry form on the Business Day immediately preceding such Interest Payment Date. Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date (each a “Regular Record Date”) and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of Securities of this series not less than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Indenture.

Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed.

Dated: [    ]

I, Brian K. Shore, Vice President, Associate General Counsel and Secretary of ONE Gas, Inc., do hereby certify that Mark W. Smith is the duly qualified and elected Vice President and Treasurer of ONE Gas, Inc. and that the signature set forth above her name is her true signature.

[Signature Page to 2029 Global Note]

TRUSTEE’S CERTIFICATE OF AUTHENTICATION

This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture.

[Signature Page to 2029 Global Note]

[REVERSE OF NOTE]

ONE GAS, INC.

5.10% Senior Notes Due 2029

This Security is one of a duly authorized issue of securities of the Company (herein called the “Securities”), issued and to be issued in one or more series under an Indenture, dated as of January 27, 2014 (the “Original Indenture”), as it may be supplemented or amended from time to time, including, without limitation, Supplemental Indenture No. 7 (herein, collectively, called the “Indenture”), between the Company and U.S. Bank Trust Company, National Association (successor in interest to U.S. Bank National Association), as Trustee (herein called the “Trustee”, which term includes any successor trustee under the Indenture), to which Indenture and all indentures supplemental thereto reference is hereby made for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Company, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered. This Security is one of the series designated on the face hereof, limited in aggregate principal amount to $300,000,000.

Prior to March 1, 2029 (which is the date that is one month prior to the maturity date of the Securities) (the “Par Call Date”), the Company may redeem the Securities at its option, in whole or in part, at any time and from time to time, at a redemption price (expressed as a percentage of principal amount and rounded to three decimal places) equal to the greater of:

(1)(a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the Securities matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate (as defined below) plus 15 basis points less (b) interest accrued and unpaid thereon to the date of redemption, and

(2) 100% of the principal amount of the Securities to be redeemed,

plus, in either case, accrued and unpaid interest thereon to, but excluding, the redemption date.

On or after the Par Call Date, the Company may redeem the Securities at its option, in whole or in part, at any time and from time to time, at a redemption price equal to 100% of the principal amount of the Securities being redeemed plus accrued and unpaid interest thereon to, but excluding, the redemption date.

“Treasury Rate” means, with respect to any redemption date, the yield determined by the Company in accordance with the following two paragraphs.

The Treasury Rate shall be determined by the Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third business day preceding the redemption date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as “Selected Interest Rates (Daily)—H.15” (or any successor designation or

publication) (“H.15”) under the caption “U.S. government securities–Treasury constant maturities–Nominal” (or any successor caption or heading) (“H.15 TCM”). In determining the Treasury Rate, the Company shall select, as applicable:

(1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the redemption date to the Par Call Date (the “Remaining Life”); or

(2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields—one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life—and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or

(3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the redemption date.

If on the third business day preceding the redemption date H.15 TCM is no longer published, the Company shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second business day preceding such redemption date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Company shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Company shall select from among these two or more United States Treasury securities the United States Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

The Company’s actions and determinations in determining the redemption price shall be conclusive and binding for all purposes, absent manifest error.

The redemption price will be quoted to the Trustee in writing and the Trustee shall have no duty to determine, or verify the calculation of, the redemption price.

The Original Indenture contains provisions (including in Sections 14.2 and 14.3 thereof), and such provisions shall apply to this Security, for defeasance at any time of the entire indebtedness of this Security or certain restrictive covenants and Events of Default with respect to this Security, in each case upon compliance with certain conditions set forth therein.

The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Company and the rights of the Holders of the Securities of each series to be affected under the Indenture at any time by the Company and the Trustee with the consent of the Holders of not less than a majority in principal amount of the Securities at the time Outstanding of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities at the time Outstanding of any series, on behalf of the Holders of all Securities of such series, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security.

No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of and any premium and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed.

As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registerable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the Company in any place where the principal of and any premium and interest on this Security are payable, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees.

The Securities of this series are issuable only in registered form without coupons in denominations of $2,000 and whole multiples of $1,000 in excess thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same.

No service charge shall be made for any such registration of transfer or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith.

Prior to due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary.

All terms used in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.

This Security shall be governed by and construed in accordance with the laws of the State of New York.

INCREASES OR DECREASES IN PRINCIPAL

AMOUNT OF GLOBAL NOTE

The initial principal amount of this Global Note is $[    ]. The following increases or decreases in this Global Note have been made:

Exhibit 5.1

110 North Elgin Avenue, Suite 200 Tulsa, Oklahoma 74120-1495 Telephone (918) 595-4800 Fax (918) 595-4990 www.gablelaw.com				BOK Park Plaza 499 West Sheridan Avenue, Suite 2200 Oklahoma City, OK 73102 Telephone (405) 235-5500 Fax (405) 235-2875
		December 13, 2023

ONE Gas, Inc.

15 East Fifth Street

Tulsa, Oklahoma 74103

Ladies and Gentlemen:

We have acted as special outside counsel to ONE Gas, Inc. (the “Company”), an Oklahoma corporation, in connection with the issuance and sale by the Company of $300,000,000 aggregate principal amount of its 5.10% Senior Notes due 2029 (the “Notes”).

The Notes were sold pursuant to an underwriting agreement, dated December 11, 2023, by and among the Company, J.P. Morgan Securities LLC, Mizuho Securities USA LLC, and U.S. Bancorp Investments, Inc., as representatives of the several underwriters named therein, for themselves and as representatives of the several other underwriters named therein.

The Notes were issued pursuant to the Prospectus Supplement, dated December 11, 2023 (the “Prospectus Supplement”) and filed with the United States Securities and Exchange Commission (the “SEC”) on December 12, 2023, and the Prospectus dated February 23, 2023, filed as part of the shelf registration statement (File No. 333-269966) that automatically became effective under the Securities Act of 1933, as amended (including the rules and regulations thereunder, the “Act”), when filed with the SEC on February 23, 2023 (the “Registration Statement”).

The Notes were issued under the Indenture dated as of January 27, 2014 (the “Base Indenture”) between the Company and U.S. Bank Trust Company, National Association (successor to U.S. Bank National Association), as trustee (the “Trustee”), as supplemented by the Seventh Supplemental Indenture, dated as of December 13, 2023, between the Company and the Trustee (the “Supplemental Indenture” and the Base Indenture, as supplemented by the Supplemental Indenture, the “Indenture”). The Supplemental Indenture and the form of the Notes are each filed as exhibits to the Company’s Current Report on Form 8-K dated the date hereof.

				ONE Gas, Inc. December 13, 2023 Page 2

In rendering this opinion, we have examined and relied on the Registration Statement, the Indenture, the form of the Notes and such corporate records and other documents, and we have reviewed such matters of law, as we have deemed necessary or appropriate. We have also

conducted such investigations of fact and law as we have deemed necessary or advisable for purposes of this letter. In rendering this opinion, we have, with your consent, relied upon oral and written representations of officers of the Company and certificates of officers of the Company and public officials with respect to the accuracy of the factual matters addressed in such representations and certificates. In addition, in rendering this opinion we have, with your consent, assumed (a) the authenticity of original documents and the genuineness of all signatures, (b) the conformity to the originals of all documents submitted to us as copies, (c) each natural person signing any document reviewed by us had the legal capacity to do so, and (d) each person signing in a representative capacity any document reviewed by us had authority to sign in such capacity.

Based on the foregoing, and subject to the qualifications and limitations stated herein, we are of the opinion that:

1. The Company has the corporate power and authority to execute and deliver the Notes and perform its obligations thereunder.

2. The Notes have been duly authorized by the Company.

This opinion is limited to the laws of the State Oklahoma. We express no opinion as to the laws of any other jurisdiction, including without limitation the federal laws of the United States. The opinions expressed herein are as of the date hereof only and are based on laws, orders, contract terms and provisions, and facts as of such date, and we disclaim any obligation to update this opinion letter after such date or to advise you of changes of facts stated or assumed herein or any subsequent changes in law.

We consent to the filing of this opinion as an exhibit to a Current Report on Form 8-K to be incorporated by reference into the Registration Statement. In giving this consent, we do not admit that we are included in the category of persons whose consent is required under Section 7 of the Securities Act of 1933, as amended, or the rules and regulations of the Securities and Exchange Commission issued thereunder. This opinion letter may be relied upon by Skadden, Arps, Slate, Meagher & Flom LLP, as if it were addressed to it, for the sole purpose of rendering its opinions in connection with the offer and sale of the Notes.

Exhibit 5.2

ONE Gas, Inc.

15 East Fifth Street

Tulsa, OK 74103

Registration Statement on Form S-3 (File No. 333-269966)

Ladies and Gentlemen:

We have acted as special United States counsel to ONE Gas, Inc., an Oklahoma corporation (the “Company”), in connection with the public offering of $300,000,000 aggregate principal amount of the Company’s 5.10% Senior Notes due 2029 (the “Notes”) to be issued under the Indenture, dated as of January 24, 2014 (the “Base Indenture”), between the Company and U.S. Bank Trust Company, National Association (successor in interest to U.S. Bank National Association), as trustee (in such capacity, the “Trustee”), as supplemented by the Supplemental Indenture No. 7, dated as of December 13, 2023 (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), between the Company and the Trustee.

This opinion is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act of 1933 (the “Securities Act”).

ONE Gas, Inc.

December 13, 2023

Page 2

In rendering the opinion stated herein, we have examined and relied upon the following:

(a) the registration statement on Form S-3 (File No. 333-269966) of the Company relating to the Notes and other securities of the Company filed with the Securities and Exchange Commission (the “Commission”) on February 23, 2023, under the Securities Act,

allowing for delayed offerings pursuant to Rule 415 of the General Rules and Regulations under the Securities Act (the “Rules and Regulations”), including information deemed to be a part of the registration statement pursuant to Rule 430B of the Rules and Regulations (such registration statement being hereinafter referred to as the “Registration Statement”);

(b) the prospectus, dated February 23, 2023 (the “Base Prospectus”), which forms a part of and is included in the Registration Statement;

(c) the preliminary prospectus supplement, dated December 11, 2023 (together with the Base Prospectus, the “Preliminary Prospectus”), relating to the offering of the Notes, in the form filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations;

(d) the prospectus supplement, dated December 11, 2023 (together with the Base Prospectus, the “Prospectus”), relating to the offering of the Notes, in the form filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations;

(e) an executed copy of the Underwriting Agreement, dated December 11, 2023 (the “Underwriting Agreement”), among J.P. Morgan Securities LLC, Mizuho Securities USA LLC and U.S. Bancorp Investments, Inc., as representatives of the several underwriters named therein (the “Underwriters”), relating to the sale by the Company to the Underwriters of the Notes;

(f) an executed copy of the Base Indenture;

(g) an executed copy of the Supplemental Indenture; and

(h) the global certificate evidencing the Notes, executed by the Company, and registered in the name of Cede & Co. (the “Note Certificate”), delivered by the Company to the Trustee for authentication and delivery.

We have also examined originals or copies, certified or otherwise identified to our satisfaction, of such records of the Company and such agreements, certificates and receipts of public officials, certificates of officers or other representatives of the Company and others, and such other documents as we have deemed necessary or appropriate as a basis for the opinion stated below.

In our examination, we have assumed the genuineness of all signatures, including electronic signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as facsimile, electronic, certified, or photocopied copies, and the authenticity of the originals of such copies. As to any facts relevant to the opinion stated herein that we did not independently establish or verify, we have relied upon statements and representations of officers and other representatives of the Company and others and of public officials, including the factual representations and warranties contained in the Underwriting Agreement.

ONE Gas, Inc.

December 13, 2023

Page 3

We do not express any opinion with respect to the laws of any jurisdiction other than the laws of the State of New York.

As used herein, “Transaction Documents” means the Underwriting Agreement, the Note Certificate and the Indenture.

Based upon the foregoing and subject to the qualifications and assumptions stated herein, we are of the opinion that when duly authenticated by the Trustee and issued and delivered by the Company against payment therefor in accordance with the terms of the Underwriting Agreement and the Indenture, the Note Certificate will constitute the valid and binding obligation of the Company, enforceable against the Company in accordance with its terms under the laws of the State of New York.

The opinion stated herein is subject to the following qualifications:

(i) we do not express any opinion with respect to the effect on the opinion stated herein of any bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer, preference and other similar laws or governmental orders affecting creditors’ rights generally, and the opinion stated herein is limited by such laws and orders and by general principles of equity (regardless of whether enforcement is sought in equity or at law);

(j) we do not express any opinion with respect to any law, rule or regulation that is applicable to any party to any of the Transaction Documents or the transactions contemplated thereby solely because such law, rule or regulation is part of a regulatory regime applicable to any such party or any of its affiliates as a result of the specific assets or business operations of such party or such affiliates;

(k) except to the extent expressly stated in the opinion contained herein, we have assumed that each of the Transaction Documents constitutes the valid and binding obligation of each party to such Transaction Document, enforceable against such party in accordance with its terms;

(l) we do not express any opinion with respect to the enforceability of any provision contained in any Transaction Document relating to any indemnification, contribution, non-reliance, exculpation, release, limitation or exclusion of remedies, waiver or other provisions having similar effect that may be contrary to public policy or violative of federal or state securities laws, rules or regulations, or to the extent any such provision purports to, or has the effect of, waiving or altering any statute of limitations;

(m) we call to your attention that irrespective of the agreement of the parties to any Transaction Document, a court may decline to hear a case on grounds of forum non conveniens or other doctrine limiting the availability of such court as a forum for resolution of disputes; in addition, we call to your attention that we do not express any opinion with respect to the subject matter jurisdiction of the federal courts of the United States of America in any action arising out of or relating to any Transaction Document;

ONE Gas, Inc.

December 13, 2023

Page 4

(n) to the extent that any opinion relates to the enforceability of the choice of New York law and choice of New York forum provisions contained in any Transaction Document, the opinion stated herein is subject to the qualification that such enforceability may be subject to, in each case, (i) the exceptions and limitations in New York General Obligations Law sections 5-1401 and 5-1402 and (ii) principles of comity and constitutionality; and

(o) we do not express any opinion whether the execution or delivery of any Transaction Document by the Company, or the performance by the Company of its obligations under any Transaction Document will constitute a violation of, or a default under, any covenant, restriction or provision with respect to financial ratios or tests or any aspect of the financial condition or results of operations of the Company or any of its subsidiaries.

In addition, in rendering the foregoing opinion we have assumed that, at all applicable times:

(a) the Company (i) was duly incorporated and was validly existing and in good standing, (ii) had requisite legal status and legal capacity under the laws of the jurisdiction of its organization and (iii) has complied and will comply with all aspects of the laws of the jurisdiction of its organization in connection with the transactions contemplated by, and the performance of its obligations under, the Transaction Documents;

(b) the Company had the corporate power and authority to execute, deliver and perform all its obligations under each of the Transaction Documents;

(c) each of the Transaction Documents had been duly authorized, executed and delivered by all requisite corporate action on the part of the Company;

(d) neither the execution and delivery by the Company of the Transaction Documents nor the performance by the Company of its obligations thereunder, including the issuance and sale of the Notes: (i) conflicted or will conflict with the certificate of incorporation or bylaws of the Company, (ii) constituted or will constitute a violation of, or a default under, any lease, indenture, agreement or other instrument to which the Company or its property is subject (except that we do not make the assumption set forth in this clause (ii) with respect to those agreements or instruments expressed to be governed by the laws of the State of New York which are listed in Part II of the Registration Statement or the Company’s Annual Report on Form 10-K for the year ended December 31, 2022), (iii) contravened or will contravene any order or decree of any governmental authority to which the Company or its property is subject, or (iv) violated or will violate any law, rule or regulation to which the Company or its property is subject (except that we do not make the assumption set forth in this clause (iv) with respect to the laws of the State of New York);

(e) neither the execution and delivery by the Company of the Transaction Documents nor the performance by the Company of its obligations thereunder, including the issuance and sale of the Notes, required or will require the consent, approval, licensing or authorization of, or any filing, recording or registration with, any governmental authority under any law, rule or regulation of any jurisdiction; and

ONE Gas, Inc.

December 13, 2023

Page 5

(f) subsequent to the effectiveness of the Base Indenture, the Base Indenture has not been amended, modified, supplemented or otherwise modified in any way that affects or relates to the Notes.

We hereby consent to the reference to our firm under the heading “Legal Matters” in the Preliminary Prospectus and the Prospectus. In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations. We also hereby consent to the filing of this opinion with the Commission as an exhibit to the Company’s Current Report on Form 8-K being filed on the date hereof and incorporated by reference into the Registration Statement. This opinion is expressed as of the date hereof unless otherwise expressly stated, and we disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable laws.